Question | Answer |
earthquakes | the shaking that results from the movement of rock below the Earth's surface |
crust | The layer of rock that forms Earth's outer surface |
fault | a break or crack in Earth's lithosphere along which the rocks move |
mantle | the layer of hot, solid material between Earth's crust and core |
lithosphere | a rigid layer made up of the uppermost part of the mantle and crust |
seismologists: | scientists who measure and study earthquakes |
lithospheric plates | large pieces of the lithosphere that are always moving |
P waves | Seismic waves that compress and expand the ground like an accordion |
S waves | Seismic waves that vibrate from side to side as well as up and down |
Seismic waves | Vibrations that carry an earthquake's energy through the earth |
Surface waves | Waves that move more slowly than P waves and S waves; they can produce severe ground movements |
Seismograph | An instrument that records and measures seismic waves |
Focus | The point where the rock breaks and triggers an earthquake |
Epicenter | The point on the surface directly above the focus |
magnitude | The number that is based on the earthquake's strength |
Richter scale | It measures an earthquake's magnitude |
Mercalli scale | It rates an earthquake's damage at a certain place |
moment magnitude scale | It rates and estimates the energy released from an earthquake |
liquifaction | The process where the earth's shaking turns loose, soft soil into liquid mud |
aftershock | An earthquake that happens after a large earthquake in the same area |
tsunami | Large ocean waves caused by underwater earthquakes |
base isolated building | A building mounted on foundation designed to absorb the energy of an earthquake |
Tension | Stress that stretches rock so that it becomes thinner in the middle |
Compression | Stress that squeezes rock until it folds or breaks |
Shearing | Stress that pushes masses of rock in opposite directions, in a sideways movement |
Strike-slip fault | A type of fault where rocks on either side move past each other sideways with little up-or-down motion |
Reverse fault | A type of fault where the hanging wall slides upward; caused by compression in the crust |
Normal fault | A type of fault where the hanging wall slides downwards; caused by tension in the crust |
Plateau | A landform that has high elevation and a more of less level surface |